1. Field of Invention
This invention relates generally to the field of portable computers, and more specifically to a flexible, wearable computer that can be worn on the body and repeatedly bent in an infinite number of planes without failure of operation.
2. Description of Related Art
Definitions
A computer system is defined as comprising three basic components: an input device, an output device, and a computer. A computer is defined as comprising memory, a processor, and associated support circuitry and components. Memory comprises main memory which is volatile, and mass storage memory which is usually nonvolatile. A portable computer system is one that the user can easily carry around. Throughout this text the author will refer to a computer to mean only and specifically the main and secondary storage memory, the processor, and a power supply. The author will also use volume to characterize both the size and the mass of computers. This is because the overall density of silicon-based computers is asymptotic to a constant. Therefore, volume will necessarily indicate a maximum weight.
Integration
Small and therefore portable computers have resulted from the intersection of innovations and inventions across a wide variety of domains and fields including the arts of silicon manipulation, and mechanical and electrical design, and component integration. Integration is the process of decreasing the size of and the space between electrical elements, and it has been the pathway to power reduction and speed But size reduction accrued benefits independent of processing power. Computers that once required buildings to house and small power plants to run can now be comfortably lifted with one hand. Since integration and therefore miniaturization has brought nearly all of the advances in service levels to date, it is the major force in the creation of the prior art in portable computing and the direction of future advancement for computer construction in general.
There has been tremendous innovation and invention using integration as a means of making computers portable. Computers are available that are small enough to be lifted by one finger. The result has been explosive demand for portable computing devices. Dataquest predicts that by 1994 sales of portable computing devices will be well over $13 billion (Byte, volume 16, number Il, p. 194).
"Picocomputers" are the state of the art of integration as a means of creating portable computers (New York Times, Mar. 23, 1992). Inventors such as M. E. Jones, Jr. have developed a single chip that contain all of the elements needed for a computer. This has allowed creation of computer systems that can fit in the breast pocket of a man's jacket and run for 100 hours on a conventional flashlight battery. The major limitations of these computer systems is that they have very small amounts of memory greatly limiting the usefulness of the device for tasks to which most computer users are accustomed. They also have very small input and output devices which are slow and inconvenient to use.
Useful Portables
Other innovations include computers with increased processing abilities that must be carried with one hand. These rigid rectilinear-shaped devices fall into the classes lap-top, palm-top or hand-held computers and increase the processing and memory capacity of the picocomputer by including the required processors and memory power in a larger enclosure. For the episodic portable commuter user that spends little time actually carrying these devices, these rigid rectilinear devices provide high levels of service rivaling desk-top micro and minicomputers. For the intensive user that processes large amounts of data and must also carry the computer for long periods time, these devices have several disadvantages.
First, research has shown that people carrying these computers for long periods of time are prone to flexi carpi ulnaris tendonitis which can be painful and debilitating. This affliction is due to prolonged and simultaneous clenching of the fingers and flexing of the wrist, an action unavoidable when carrying these devices.
Second, for intensive data acquisition applications, size once again is a constraint. The amount of secondary memory required for implementation makes this option impractical for portable computers in rigid rectilinear packaging. On-board memory requirements have been sidestepped by including wireless data links to a host computer for down-loading data. However, these options are very costly, up to the cost of the computer itself, and increase the volume of the devices by as much as a factor of two. Furthermore, wireless communication is presently a very slow data transfer process.
Third, field service research for Rockwell International has demonstrated that user compliance of rigid rectilinear hand-carried and hand-held computers is low, and gets lower as the size of the device increases. Field service personnel expressed considerable displeasure with having to lug a "brick" around during the execution of their task. Most notably it restricted the use of their hands by virtue of one, or both being used to carry the computer.
Wearable Portables
There has been innovation and invention to harness rigid rectilinear computers on various parts of the body. Reddy Information Systems Inc. has produced a computer called Red FIG. 1 that has a head mounted output device (A) from Reflection Technologies called the Private Eye, and a belt-mounted rigid rectilinear-packaged computer and input device (B) secured by a belt harness (C) (New York Times, Mar. 29, 1992). Infogrip Inc. and Select Tech Inc. have combined technologies to produce the Hip Pc in a similar configuration.
There are two main disadvantages to this approach. First, harnessing a rigid rectilinear-packaged computer anywhere on the body creates an uneven load on the spine. Prolonged wearing of such devices creates strain in the supporting muscles opposite the place where the computer is harnessed. Second, these configurations do not allow the human body to comfortably contact a firm surface. The rigid rectilinear computer on a harness or belt is literally a lump on the surface of the body. Lastly, rigid rectilinear designs are inherently limited in expandability. To increase processing power, hardware size must be increased. There is a volume limit beyond which the computer is no longer portable.
There has been innovation and invention to make computers more comfortable to wear. Hideji Takemasa of NEC Corp. has created a variety of rigid curvilinear-packaged computer models that conform to various parts of the body FIG. 2 (Fortune, Jan. 13, 1992). These devices include a processor and CD-ROM reader (D), and a fold out input/output device (E,F). Although aesthetically more appealing than the rigid rectilinear lumps of the Red and Hip PC models, the NEC models nonetheless suffer the same disadvantages. The NEC curvilinear designs are rigid and dynamically nonconforming and subject the spine to uneven loading. They also do not allow comfortable contact of the human body with firm surfaces. Furthermore, these rigid, curvilinear designs must be made in many sizes since it is technically impossible to make one of these designs fit all human morphologies. They are also inherently limited in expandability just as the rigid rectilinear designs.